DS1087L Datasheet, PDF (11/12 Pages) Dallas Semiconductor – 3.3V Spread-Spectrum EconOscillator

3.3V Spread-Spectrum EconOscillator
SDA
t_BUF
SCL
STOP START
t_LOW
t_HD:STA
Figure 5. 2-Wire AC Characteristics
t_R
t_F
t_HD:STA
t_HD:DAT
t_HIGH
t_SU:DAT
t_SU:STA
REPEATED
START
t_SP
t_SU:STO
TYPICAL 2-WIRE WRITE TRANSACTION
MSB
LSB
MSB
LSB
MSB
LSB
START
1
0
1
1
A2*
A1*
A0* R/W
SLAVE
ACK
b7
b6
b5
b4
b3
b2
b1
b0
SLAVE
ACK
b7
b6
b5
b4
b3
b2
b1
b0
SLAVE
ACK
STOP
DEVICE IDENTIFIER
DEVICE READ/
COMMAND/REGISTER ADDRESS
DATA
ADDRESS WRITE
EXAMPLE 2-WIRE TRANSACTIONS (WHEN A0, A1, AND A2 ARE ZERO)
B0h
02h
DATA
A) SINGLE BYTE WRITE
-WRITE PRESCALER
START 1 0 1 1 0 0 0 0
SLAVE
ACK
00000010
SLAVE
ACK
10000000
SLAVE
ACK
STOP
REGISTER TO 128
B) SINGLE BYTE READ
-READ PRESCALER
REGISTER
B0h
02h
B1h
DATA
START 1 0 1 1 0 0 0 0
SLAVE
ACK
00000010
SLAVE
ACK
REPEATED
START
10110001
SLAVE
ACK
10000000
MASTER
NACK
STOP
*THE ADDRESS DETERMINED BY A0, A1, AND A2 MUST
MATCH THE ADDRESS SET IN THE ADDR REGISTER.
Figure 6. 2-Wire Transactions
Application Information
Power-Supply Decoupling
To achieve the best results when using the DS1087L,
decouple the power supply with 0.01µF and 0.1µF
high-quality, ceramic, surface-mount capacitors.
Surface-mount components minimize lead inductance,
which improves performance, and ceramic capacitors
tend to have adequate high-frequency response for
decoupling applications. These capacitors should be
placed as close to the V_CC and GND pins as possible.
Stand-alone Mode
SCL and SDA cannot be left floating even in stand-
alone mode. If the DS1087L never needs to be pro-
grammed in-circuit, including during production
testing, SDA and SCL can be wired high.
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